54 research outputs found
Measurement of spin-polarized photoemission from wurtzite and zinc blende gallium nitride photocathodes
No full textSpin-polarized photoemission from wurtzite and zinc blende gallium nitride (GaN) photocathodes has been observed and measured. The p-doped GaN photocathodes were epitaxially grown and activated to negative electron affinity with a cesium monolayer deposited on their surfaces. A field-retarding Mott polarimeter was used to measure the spin polarization of electrons photoemitted from the top of the valence band. A spectral scan with a tunable optical parametric amplifier constructed to provide low-bandwidth light revealed peak spin polarizations of 17% and 29% in the wurtzite and zinc blende photocathodes, respectively. Zinc blende GaN results are analyzed with a spin polarization model accounting for experimental parameters used in the measurements, while possible mechanisms influencing the obtained spin polarization values of wurtzite GaN are discussed
Deseret Telegraph Office Rockville Ut. P.6
No full textThe Deseret Telegraph and Post Office Building, Rockville, Utah
High speed, large deflection deformable mirrors for focus and spherical aberration control
No full textInhibition of IL-4-inducible gene expression in human monocytes by type I and type II interferons
No full textAbstract
The Th2-type cytokines, interleukin-4 (IL-4) and interleukin-13 (IL-13), induce expression of a distinct subset of genes in human monocytes, including Fc∊RIIb (CD23), 15-lipoxygenase, IL-1 receptor antagonist (IL-1ra), and type I and type II IL-1 receptors (IL-1R). Type I interferons (IFN-α and IFN-β) and type Ii interferon (IFN-γ) inhibit induction of these genes by IL-4 and IL-13. However, the mechanism by which IFNs mediate this inhibition has not been defined. In this overview, we discuss the role of the transcription factor, STAT6 (signal transducer and activator of transcription-6) in mediating IL-4- and IL-13-induced gene expression in monocytes. We also discuss our recent findings that type I and type II IFNs suppress IL-4/IL-13-inducible gene expression by inhibiting tyrosine phosphorylation and nuclear translocation of STAT6. The ability of type I and type II IFNs to inhibit IL-4/IL-13-induced STAT6 activity is dose-and time-dependent, and is not unique to monocytes because IFNs induce the same effects in fibroblasts. Inhibition of STAT6 activity is not evident unless cells are preincubated with IFN for at least 1 h before IL-4 stimulation. Furthermore, inhibition can be blocked by actinomycin D, indicating a requirement for de novo transcription. We propose a model in which stimulation of monocytes by IFN activates de novo synthesis of an inhibitory factor, possibly one or more members of the SOCS/SSI/CIS gene family, capable of suppressing activation of STAT6 by IL-4 and IL-13. Because STAT6 activation plays an essential role in IL-4/IL-13-induced gene expression, the ability of IFN-β and IFN-γ to inhibit STAT6 activity provides an explanation for how IFNs can suppress IL-4/IL-13-inducible gene expression. J. Leukoc. Biol. 65: 307–312; 1999.</jats:p
COMORBID DIABETES AND DEPRESSION AND INCREASED RISK FOR COGNITIVE IMPAIRMENT IN MEXICAN AMERICANS
No full textBackground: By 2050, the percent of Hispanics in America age 65 and above will nearly triple compared to other ethnic groups. During this timeframe, the numbers of Alzheimer’s disease (AD) and Mild Cognitive Impairment (MCI, a prodromal stage to AD) cases among Hispanic elders is expected to grow exponentially. Given that 65% of the U.S. Hispanic population is Mexican American (MA), this ethnic group represent the fastest growing segment of the aging population, which will be disproportionately impacted by MCI and /AD in the near future. Recent work from our group suggest that depression is a significant risk factor for MCI and AD among Mexican Americans while many other “established” risk factors among non-Hispanic whites (i.e. education, gender, hypertension, diabetes, ApoEε4 genotype) are not. Another important risk factor among this population is diabetes (DM). Depression and DM have been shown to be pathologically linked several times in the past, however little research has examined the affect that comorbidity of depression and DM has on cognitive impairment in an ethnically diverse sample Purpose (a):
To determine whether there is a connection between depression, diabetes and Alzheimer's disease in the Mexican American population. Methods (b): Methods: This study used data from three separate cohorts: HABLE, TARCC, and Project FRONTIER. In HABLE data was collected from 208 MA (AGE= 62years; EDU=7years); TARCC had 2080 Non- Hispanic white (AGE=75; EDU=15years) and 543 MA (AGE=70; EDU=11); Project FRONTIER had 330 non-Hispanic white (AGE=65; EDU=13) and 233 MA (AGE=55; EDU=7years). Logistic regression analyses were conducted to examine comorbid diagnosis of depression and diabetes on Alzheimer’s disease diagnosis or a diagnosis of Mild Cognitive Impairment. Covariates entered into the model were age, education, and gender. Results (c): Results: Comorbid diagnosis of diabetes and depression was significantly related to diagnosis of Mild Cognitive Impairment in Mexican Americans across all three cohorts: TARCC (odds ratio [OR]= 8.6, 95% CI=1.5 to 2.7); HABLE (odds ratio [OR]= 2.4, 95% CI= 1.3-3.2), and FRONTIER (odds ratio [OR]= 2.6, 95% CI=1.2 to 6.4). TARCC was the only cohort with a large enough sample of AD patients to run the analyses split by ethnicity. In TARCC, comorbidity was related to AD diagnosis in MA (odds ratio [OR]= 10.4, 95%=1.2-2.7), and narrowly related in Non-Hispanic Whites (odds ratio [OR]= 8.3, 95%=.14 to 1.4). Conclusions (d): Discussion: Comorbid diagnosis of depression and diabetes increases risk for diagnosis of cognitive impairment, and Mexican Americans were found to be at greater risk than non- Hispanic whites for Mild Cognitive Impairment. These findings were validated across multiple cohorts, and could have significant clinical implications
Polarization-selective optical nanostructures for optical MEMS integration
No full textOptical nanostructures have the potential to provide useful new functionalities, using materials and fabrication methods that are compatible with standard silicon-based processes. For example, it has been shown that a nanoscale grating coated with a metal layer produces polarization-selective reflectivity [1,2], based on the combined effects of form birefringence and a resonant cavity [3]. In this work, we adapt this design approach to develop two devices optimized to operate around 1.55 μm wavelength: a polarizing beam splitter, and a polarization-selective reflector. Such devices are of particular interest as they may provide optical properties such as polarization selectivity or enhanced reflectivity using nanostructures compatible with optical micro-electro-mechanical systems (MEMS).OP
Nanostructured effective-index micro-optical devices based on blazed 2-D sub-wavelength gratings with uniform features on a variable-pitch
No full text- …
